Should I buy the AT-200 or AT-300 AutoTune?

If you have a 2 cylinder bike with a PCV, you have a choice to use either the dual channel kit (AT-300) or the single channel kit (AT-200). The dual-channel AutoTune kit tunes more accurately (cylinder advanced), but is more expensive. Some people don’t feel the gains outweigh the cost, but others do. The gains to be made with dual channel over single channel are dependent on the bike model. On an air cooled V-twin, the cylinders are going to need different fuel quantities because of the cooling differences. A parallel or boxer twin would have very similar cylinder temps, and have similar fuel requirements. There is also exhaust airflow differences to consider, a V-Twin has very different flow from cylinder to cylinder; other types of twins have nearly identical exhaust flow from cylinder to cylinder. It’s a judgment call which is best for your bike.